Gas turbine engines contain a number of turbine modules each containing a plurality of vanes and blades for exchanging energy with a working fluid medium. Since the vanes and blades of a turbine module operate in a high temperature gas stream, they are typically constructed of high temperature nickel-based, cobalt-based, or iron-based superalloys. They are further coated with oxidation and corrosion resistant coatings. Preferred coatings are aluminide and MCrAlY coatings where M is nickel, cobalt, iron, or mixtures thereof. Aluminide coatings are compounds that contain aluminum and usually one other more electropositive element such as cobalt or platinum. When the coatings are applied to the parent superalloys, a diffusion layer is formed beneath the aluminide coating layer that is oxidation resistant.
In engine run turbine modules, it is sometimes necessary to remove selected areas of vane and blade surfaces in order to restore various features of the surfaces to their original condition. If this restoration can be performed in situ without disassembling a module, considerable time and money is saved.